<!DOCTYPE html>
<html lang="zh-cn">
<head>
	<meta charset="utf-8">
	<title> css 入门 </title>
	<style>
		#first_p, #second_p{
			border: solid 1px red;
		}
		#second_b{
			border: inherit;
		}
	</style>
</head>
<body>

	<p id="first_p">这里的段落中<b id="first_b">加粗部分文字</b>没有边框</p>
	<p id="second_p">这里的段落中<b id="second_b">加粗部分文字</b>有边框</p>

</body>
</html>